Apple has released iOS 5.1 Beta 3 (build 9B5141a) for download both over the air for existing Beta users and for general download at the developer portal. The update changes the baseband firmware from 1.4.00 to 1.5.04 (possibly fixing some stability issues) and appears to restore the 3G toggle switch, a welcome move for those who live in places with spotty 3G coverage.
Apple restores 3G toggle switch in iOS 5.1 Beta 3
Apple restores 3G toggle switch in iOS 5.1 Beta 3/
Apple has released iOS 5.1 Beta 3 for download, and it appears the previously removed 3G toggle switch has been restored.